Production of catalytic material



and have not Patented Jan. 10, 1933 rATEs JAGGB ALBERT WEEK, 01? MANCHESTER, ENGLAND, ASSIGNQR TO IMIEBIQL COAL INDUSTRIES LIMITED, OF LONDON, ENGLAND PBODUGTIQN' OF CATALYTIC MATERIAL Ho Drawing. Application filed Kay Q1, 1930, Serial No. 454,513, and, in Great Britain dune 1, 1929.

This invention relates to the production of catalytic material, and more articularly to an advantageous form of suc .material for the catalytic oxidation of S0 on a large scale.

The object tion of a catalytic material in that it does not readily change characteristics with use.

Catalytic masses have been proposed comprising vanadium compounds, aixed with silicious material with or without the addition of alkali salts. These masses whilst having adequate activity are of a friable nature had the requisite physical strength for practical use.

It has also been proposed to combine the vanadium compound with the whole or part of the silica to form a complex compound resembling zeolite.

lhe invention consists in the preparation of a catalytic material by a physical admixture of a vanadium compound with a silicious diluent and a silicious hydrogel.

The invention also consists in the preparation of a catalytic'mass of satisfactory activity and adequate physical strength'by a simp e admixture of a vanadium compound with a silicious material of which a part at least is in the form of a wet hydrogeli The invention also consists in the process of the invention is the producsuch a form its physical which comprises production of hard pellets or masses consisting of making a mixture of a soluble vanadium compound, a silicious diluent, and a silicious hydrogel, and forming the mixture into pellets or masses by any suitable means, such pellets or masses being treated after drying with burner gas at an elevated temperature.

The-invention also consists in the preparation of a catalytic mass in pellet form by mixing a silicious hydrogel with an inert silicious diluent and a vanadium compound, and formin the resultant mass into a pellet preferably eating the pellets with burner gas at an elevated temperature.

The invention also consists in the process which comprises the employment of pellets or masses prepared accordin to either of the preceding two paragraphs, or the catalytic oxidation of sulphur dioxide to sulphur trioxide.

The invention also consists in'processes for the production of catalytic material substantially as described, and in catalytic material which may be made by those processes or by the equivalents thereof. 7

In carrying the invention into efi'ect, the following examples are given, references to parts being to parts by weight Ewamgole 1 A solution of potassium silicate containing about 2 grms. K 0 per litre and having a molecular ratio of K 0 silica=1:3.3et is prepared.

120 parts finely ground silica are stirred with 310 parts normal sulphuric acid and suihcient of the potassium silicate solution is added to exactly neutralize the acid. Thorough agitation is continued and the mixture gently warmed, After a short time the mixture will set to a white gelatinous mass, which is then allowed to stand 24 hours, by which time a small amount of watery liquid will have separated. This liquid is poured away, and the gelatinous mass mashed up with20 to 24 parts potassium meta vanadate dissolved in 50 parts water. The thick paste thus produced is then dried at a lowtemperature on a water bath when it falls to a white powder. This powder is compressed into tablets or pellets which are then dried for 4 hours at 180 C. and afterwards heated in a current of air at a gradually rising temperature up to 400 C. The heating is continued in a stream of burner gas containing 7-8 per cent. S0 the temperature being gradually raised to 500 C. Catalysis will commence a few minutes after the burner gas is turned on. The resultant bright yellow pellets constitute an excellent catalytic mass for the conversion of S0 to SO liquor and mixed with parts calcined kieselguhr. A solution of ammonium vanadyl oxalate is prepared by adding oxalic acid to a suspension of 18 parts ammonium vanadate on 200 arts boiling water until a clear deep blue so ution results. This solution is evaporated to a. bulk of about 50 equvalent volumes and added to the paste of gel and kieselguhr. The whole is now dried on a water bath, and the bright blue powder produced is compressed into pellets which are dried and treated with air and burner as as described in Example 1. The brownis ellow pellets thus produced are an excel ent catalyst for the oxidation of SO to S0,.

General The vanadium compound used may be either in the pentavalent or tetravalent form, and is preferably in the form of a soluble salt such as alkali vanadates, alkali vanadltes, vanadyl salts or double salts such as vanadyl sulphate, or ammonium vanadyl oxalate.

The silicious material may consist of a finely pulverulent body such as finely ground silica, silicious brick, sand or kieselguhrmixed with wet silica gel.

The pasty mixture of gel and silicious diluent together with the requisite vanadium compound is dried and compressed into pellets. Alternatively the thick pasty mass either with or without partial drying may be extruded through an aperture and the vermiform damp mass dried and broken up. The pellets or lumps are then thoroughly dried and heated to 400 C. or thereabouts in a current of air, and finally treated with burner gas containing S0 and oxygen at a temperature of from 450 C. to 500 (3., when catalytic masses of high activity and suitable physical strength result.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is 1. A process for the preparation of a catalytic material, which consists in mixing together a vanadium compound, a silicious diluent and a silica hydrogel substantially in unreacted form.

2. A process for the production of hard substances which consists in mixing together a soluble vanadium compound, a silicious diluent and a silica hydrogel substantially in unreacted form, and forming the mixture into substances of the desired size and shape.

3. A process as claimed in claim 2, in which the substances when substantially dry are treated at an elevated temperature.

4. A process as claimed in claim 2, in which the substances when substantially dry are treated with burner gas substantially in unreacted form.

5. The process which comprises the preparation of a catalytic mass in pellet form by mixing a silica hydrogel substantially in unreacted form with an inert silicious diluent and a vanadium compound, and forming the resultant mass into a pellet, and heating the pellets with burner gas at an elevated temperature.

6. The process which comprises contacting a mixture of sulfur dioxide and air with the catalyst pre ared in accordance with claim 2.

7 A cata yst composition comprising silica el substantially in unreacted form con taining a silicious diluent and a vanadium oxide distributed therethrough.

8. A catalyst composition prepared by mixing toget er a vanadium compound, a silicious diluent and a silica hydrogel substantially in unreacted form, drying the composite mixture and heating at an elevated temperature.

In testimony whereof, I afiix my signature.

JACOB 'A. WEIL.

CERTHFICATE 0F CORRECTION.

.ianuary 10, 1933.

. Fatent No. 1,893,812.

JACOB ALBERT WEIL.

it is hereby certified that error appears in the printed specification of the Page 2, lines 59 and above numbered patent requiring correction as follows: 64), strike out the words "substantially in unreacted form"; and that the said Letters Patent should be read with this correction therein that the same. may

coniorm to the record of the case in. the Patent Office.

Signed and sealed this 28th day of February, A. D. 1933.

M. 5., Moore, I

Acting Commissioner of Patents.

(Seai) 

